Sandwich-like SnO2/Cu@Carbon composites with long-term cycling stability as lithium-ion battery anodes

Abstract

Tin-based anode materials have emerged as a promising candidate for lithium-ion batteries due to its inexpensive cost and high theoretical specific capacity, whereas its potential application is limited by severe capacity attenuation and inferior cycling stability due to the huge volume fluctuation during lithiation/delithiation. Herein, SnO2/[email protected] composite was fabricated to overcome this problem through a facile co-precipitation approach followed by carbon coating. In the as-prepared composite, SnO2 and Cu particles are uniformly embedded in N-doped carbon network matrix. Such unique sandwich-like product can greatly alleviate the large volume expansion and SnO2 aggregation that is conducive to the electron/ion migration, and significantly improve cycling permanence. Therefore, the optimized sample shows impressive long-term stability even at high current density of 1.0 A g−1 (348 mAh g−1 after 1000 loops without obvious capacity decay). Moreover, a comprehensive dynamic analysis of the lithium storage was performed, implying that the increased Li+ diffusion coefficient and pseudocapacitive contribution after cycling may account for the improved electrochemical performances.